The invention relates to the field of filtration and, more particularly, to a frame of a filter pack.
Filters are frequently used in air handling systems. Such filters typically include filter packs having filtration media inside some form of media support. One type of filter has the media positioned within a rigid frame of either metal, cardboard, wood or plastic. The additional material from which the frame is made, however, can be expensive. Further, making frames of metal, plastic, wood or cardboard is undesirable since such materials are materials which, above and beyond those normally needed in filter manufacture, must be kept on hand by the manufacturer.
Bag filters have filtration media sewn into bag shaped pockets which extend away from the filter header when in use. This type of filter also has disadvantages including the need for room for the bag filter to extend into, the filter bags collapsing when not in use, and the possibility of damage to the filter media when installing. Further, when a bag filter collapses during non-use and then inflates and extends during use, material which had been filtered from air handled by the filter can be shaken loose, and some of this material can re-enter air being treated.
A further disadvantage with existing framed filters is that they can be difficult to dispose of depending upon how they were used. For example, it is possible that a filter will be used to treat air which is considered contaminated. When a filter has been used in this way, disposal must be handled specially. Incineration would be one possibility, but this is precluded when the frame is a non-flammable material such as metal.
The usual filter has frames made out of cardboard, metal, plastic or wood. The use of these frame materials usually requires the filter manufacturer to work with suppliers that specialize in the named materials, in how to treat the materials, how to shape them, cut them, etc. These suppliers add another link in the economic chain which has its own technology, priorities, production cycles, profit demands, etc.
Cardboard filter frames do have a relatively low cost, but they are not water resistant. With new synthetic filter medias, the filter pack usually can last much longer than the cardboard frame; unfortunately, the filter has to be replaced because of frame failure, and using plastic or metal frames makes the filter very expensive.
Filter manufacturers usually have to have a great inventory of framing material and/or frames in order to satisfy demands of customers, and this inventory requires much space, much inventory (in very many sizes) and much personnel for inventory management and the like. For example, for metal frame filters, all different casing sizes must be kept in stock, and these include 20×20, 24×20, 16×20, 16×24, etc.
In connection with manufacture, if a filter manufacturer buys metal on a coil, that manufacturer then needs to have metal handling equipment, cutting equipment, bending equipment, rolling equipment, stamping equipment and the like. For plastic, all forming and extrusion equipment is needed. For wood, saws, dust collection and fire protection equipment are needed.
Based upon the foregoing, it is clear that the need exists for an improved frame for filter packs which addresses these various issues.
It is the primary object of the present invention to provide a solution to these issues.
Other objects and advantages of the present invention will appear herein.